Example TEM micrographs. (a) Histologically normal rectal cell nuclei from control patients and those harboring a pre-cancerous adenoma elsewhere in the colon, representing field CRC. Scale bars correspond to 500 nm. (b) Histologically normal colonic cell nuclei from control rats and those treated with azoxymethane for 10 weeks (premalignant time point), representing early CRC. Scale bars correspond to 250 nm.